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The medical sterilization paper plastic packaging bag is a disposable medical sterilization packaging material, which has the advantages of good air permeability, good penetration of sterilization medium, high bacteria resistance after sterilization, convenient chemical monitoring during sterilization, simple package sealing, good perspective, long safety period after sterilization, easy opening, etc., and can also significantly reduce the procurement cost and facilitate waste recycling, meeting environmental requirements, It is a kind of medical sterilization packaging material with the best comprehensive performance.

However, in the actual production of medical sterilization paper plastic packaging bags, there are often some problems. Here, the author mainly discusses the common problems in material selection and design of sterilized paper plastic packaging, and how to solve them, and share them with the industry.

1. Correct material selection is the first step of medical sterilization packaging manufacturing

According to ISO 11607-1:2006 (i.e. GB/T 19633-2015 in China), EN 868-5:2009 (i.e. YY/T 0698-2009 in China) and the requirements for sterilization packaging, medical sterilization packaging materials must meet the following basic requirements:

Compatibility with sterilized devices

The nature and intended use of the device determine the sterilization method to a certain extent, and different sterilization methods affect the material selection of the packaging system.

For example, ethylene oxide sterilization is not applicable to articles with strong adsorption; Instruments with PE parts are not resistant to high temperature and are not suitable for high-temperature steam sterilization; For expensive instruments, generally choose the sterilization method with short sterilization cycle to improve the use frequency. Therefore, the nature of the device itself determines the packaging system to be adopted to a certain extent.

Adapt to the sterilization method adopted

After the packaging materials are subjected to the specified sterilization methods, their performance shall be within the specified limits.

For example, ethylene oxide sterilization requires that at least one of the materials constituting the packaging system has air permeability to ensure that ethylene oxide can enter during sterilization and can be resolved after sterilization.

Irradiation (gamma ray) sterilization does not have high requirements for paper, but has a great impact on polymer materials. Therefore, all packaging materials constituting the packaging system are required to be resistant to radiation treatment without aging and embrittlement.

For high temperature steam sterilization, all materials constituting the packaging system shall be able to withstand high temperature, usually at 121 ℃ - 134 ℃ for 15-30 minutes.

Low temperature formaldehyde sterilization basically requires the same materials as steam sterilization, but the penetration of formaldehyde gas is relatively poor.

Plasma sterilization requires that the packaging materials constituting the packaging system should be free of biological fibers, because these materials can quickly interact with oxidants and their superoxide free radicals, which leads to insufficient concentration of sterilizer, leading to sterilization failure.

Sufficient penetrability

Packaging materials shall facilitate the entry and exit of sterilization factors to ensure the sterilization effect.

Microbial barrier

Microbial barrier refers to the ability of the packaging system to prevent microorganisms from entering under specified conditions.


Packaging materials shall have sufficient strength to prevent damage during sterilization. It includes peel strength, tensile strength, puncture strength, tear strength and bursting strength of materials.


The material itself does not contain any components with potential risks, and also includes the surface coating components of some packaging materials. Under the normal and designated sterilization environment, the material is stable, does not decompose, do not split, and does not transfer potentially harmful substances to the surface of the packaged device.

It is allowed to open and use aseptic packaging

There are high requirements for the materials that make up the packaging system and the heat sealing between different materials. When the package is opened, there shall be no fiber chips.

The paper plastic packaging bag for medical sterilization is a part of the medical sterilization packaging. While the selection of materials meets the above requirements, there are also some other requirements. For example, the paper of medical sterilized paper plastic packaging bags should not be decolorized, the PH value of the paper extract should be within the range of 5 and 8, the fluorescence brightness should not be greater than 1%, the UV radiation source should be irradiated at a distance of 25 cm, the number of fluorescent spots with an axis length of more than 1 mm per 0.01 square meter should not exceed 5, the hydrophobicity of the paper is that the penetration time should not be less than 20 seconds, the average aperture of the paper should not exceed 35 microns, and the maximum value should be less than 50 microns, As well as the air permeability and water absorption of paper, there are also certain requirements, which also need to meet the requirements of paper printing.

In addition, the operability of materials should be fully considered in the selection of medical sterilization paper plastic packaging bags. For example, PP film and PE film are very common plastic films. Although these plastic films also meet the requirements of medical packaging materials, they are rarely used directly in medical paper plastic packaging bags. Because they are not convenient for bag making, most of them are used after PP film or PE film is compounded or co extruded with other materials.

The correct material selection has laid a solid foundation for the production of perfectly sterilized paper plastic packaging bags.

2. Product design is also an important link that cannot be ignored

A qualified medical sterilization package cannot be separated from reasonable design. From packaging style to production, manufacturing and processing, full consideration should be given.

When designing the packaging, the characteristics and needs of the product itself should be considered as much as possible: products that need to avoid light can not be packaged with paper and plastic, but aluminum foil composite bags or paper aluminum composite bags should be used; Products with a certain thickness are packed in paper plastic bags, which are more beautiful and reliable than those packed in air permeable bags with middle seams; Products that need large air permeability should be packaged in paper plastic bags or full paper bags as far as possible; Products that need moisturizing or liquid should be packaged with good barrier materials.

The following are some problems that are often ignored, and we hope to draw the attention of insiders:

(1) Design of Stripping and Opening Paper Plastic Packaging Bag

For the paper plastic packaging bags on the market at present, in order to facilitate the opening of the paper plastic bags, the plastic film and dialysis paper are generally misaligned by no less than 1mm (as shown in Figure 1) at the end where the paper plastic bags are peeled and opened, and semicircle incision is not used as far as possible. Because the semicircular incision is too small and shallow (as shown in Figure 2), it is inconvenient for the thumb to operate, and the real meaning of the incision is lost; The cutting is too big and too deep. Although it is convenient to separate the plastic film from the dialysis paper, the effective area is wasted, or the handle is too small after separation (as shown in Figure 3).

The ideal design is easy to peel and open. In addition to the dislocation of the two layers of materials, the paper at the opening is cut into a rectangular notch about 3~4mm wide, which is not only convenient for the separation of the plastic film and dialysis paper, but also convenient for both hands to handle after separation, and the overall use area is not expensive.

In addition, for a large part of medical paper plastic packaging bags, in order to open easily, V-shaped sealing ironing is selected for the opening edge (as shown in Figure 5). In this way, although it is convenient to open, during sterilization, especially in the case of steam sterilization, the V-shaped place is prone to burst. In order to solve this problem, a reinforcing strip (as shown in Figure 6) is added to the inner concave of the V-shaped, which can better meet the requirements of steam sterilization.

(2) Anti paper scraps design of paper plastic packaging

When the paper plastic packaging bag is peeled and opened, it is easy to have paper scraps. After this happens, most bag making operators will think it is due to improper operation or materials. Of course, some are really due to the nature of the material, such as poor uniformity of the coated paper and glue, and unreasonable adhesive strength of the glue itself; There is also the phenomenon of paper scraps when peeling due to excessive peeling strength caused by misoperation. However, there is still a large part of the reason, because of the negligence in the design, we did not really understand the essence of the paper plastic when ironing and bag making, which led to the paper scraps when peeling and opening.

In the bag making process of paper and plastic packaging bags, most of them are formed by hot pressing, cooling and cutting of a fixed shape mold.

Whether heating and ironing on one side of the plastic film surface or dialysis paper surface, or heating and ironing on both sides at the same time, the ironing principle of the plastic film and dialysis paper is to melt the heat sealing layer on the plastic film surface, combine it with the coated layer or treated surface of the dialysis paper, or the untreated surface, and then press it with a certain pressure through the ironing die, and cool and solidify it with the cooling device to make the dialysis paper and the plastic film have a certain peeling strength.

During the hot pressing and ironing process of the paper plastic packaging bag, when the ironing mold is being sealed and ironed, the mold forms a force with the platform below and the silicone pad, which can make all the ironing parts (hot seams) as evenly as possible. However, the pressure at each edge of the mold is greater than that at other places. To ensure that the overall peel strength of the hot seam is within a certain range, the peel strength at the most edge will be greater than that at other places. This often leads to paper scraps when peeling and tearing. It is relatively simple to solve the problem of paper scraps caused by high peeling strength at the most edge. It is only necessary to grind all edges and corners of the pressed mold and the paper plastic contact surface into a certain arc shape.

There is also a situation that is easy to cause paper scraps when peeling and opening, which is also the most easily overlooked aspect. In the process of cutting and forming, whether it is horizontal or vertical hot pressing bag making, the position of the cutter and the round cutter is the key to cut off or roll off the leftovers at the edge of the bag. As we have said before, the ironing between the paper and the membrane is based on the melting of the thermal seal layer of the membrane, which partially penetrates into the ironing surface of the dialysis paper, thus forming the peeling strength between the plastic film and the dialysis paper. When our cutter cuts the plastic film and dialysis paper, the cutting principle is similar to that of scissors. If the blade of the cutter is not sharp enough, the plastic film and dialysis paper will occlude each other at the cutting position. If the cutter cuts at the hot joint of the plastic film and dialysis paper, the occluding condition will be more serious.

When the peeling is opened, on the one hand, because the fiber on the cut end is destroyed when the dialysis paper is cut, the plastic film is no longer peeled off from the fiber on the surface of the dialysis paper, but from the fiber on the end face where the dialysis paper is cut, so it is easy to produce paper scraps; On the other hand, because the peeling strength of the incision edge is actually the sum of the strength of the plastic film and dialysis paper when they are ironed together and the strength of the plastic film and dialysis paper when they are cut off by the cutter, it is easy to have paper scraps when peeling off.

To avoid paper scraps caused by peeling, it should be considered in the design that the transverse bag making and ironing mold is slightly narrower than the actual bag width. After the bag is sealed and ironed, there should be a gap between the first bag and the second bag ironing mold. When the cutter cuts, it is required to be between the gaps to ensure that there is a gap outside the hot seam edge of each bag; There is also a gap outside the two hot seam edges when the longitudinal bag making irons the edge of the cutting residue.

That is to say, when cutting, the knife should not be cut on the hot seam (the hot joint of the plastic film and the dialysis paper), but should be cut outside the hot seam. In order to meet this requirement, packaging bags with printing must be designed with this in mind.

(3) Folding position design of tape sealing for medical self sealing bags

In the medical sterilization paper plastic packaging bags, there are also some medical self sealing bags. Medical self sealing bags are also called medical self-adhesive bags, self sealing flat bags or self-adhesive flat bags.

The sealing of the medical self sealing bag is the release paper that removes the double-sided adhesive tape from the bag mouth. After folding, one half of the width of the double-sided adhesive tape is pasted on the plastic film, and the other half is pasted on the dialysis paper. In order to meet this requirement, fold line positioning and form have also undergone several improvements.

At first, the folding line is printed at the folding position (as shown in Figure 8), and is folded along the printing folding line when folding. However, it is easy to shift and deflect when folding. In order to better position and facilitate folding, cut the dotted line of dialysis paper at the folding position.



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